1. Field of the Invention
The present invention relates to a battery pack, a battery discrimination control apparatus, and a method therefor, all of which are applied to a data processing apparatus assumed for use in a portable state.
2. Description of the Related Art
Various types of compact, lightweight data processing apparatuses such as personal computers in consideration of portability have been recently planned and sold. In a data processing apparatus of this type, the continuous operating time of the data processing apparatus is limited because a secondary battery such as a nickel-cadmium (to be referred to as Ni-Cd hereinafter) or nickel-hydrogen (to be referred to as NiH hereinafter) battery is used as a power supply. The battery capacity may be increased to prolong the continuous operating time of the apparatus, but the data processing apparatus becomes bulky and heavy as a whole. Under these circumstances, strong demand has arisen for a battery having a sufficiently high power efficiency. No battery which satisfies this requirement has been proposed. At present, a battery having a large power capacity within the allowable range in consideration of the size and weight of the apparatus is mounted and used. Therefore, if a user wants to continuously operate the apparatus for a long period of time, a supplementary battery is prepared or an AC adapter is connected to the apparatus at the sacrifice of portability and mobility.
A battery using lithium ions (to be referred to as Li ions hereinafter) has been recently developed as a secondary battery having a capacity equivalent to at least an NiH battery and a great reduction in weight. The Li ion batteries have been practically used in some home electric appliances.
The Li ion battery has charge/discharge characteristics greatly different from those of the conventional Ni-Cd and NiH batteries. In particular, when the Li ion battery is charged under the same control as in the Ni-Cd and NiH battery, the Li ion battery may easily explode. For this reason, dedicated power control is required for the Li ion battery. The Li ion battery cannot be used in place of the conventional Ni-Cd or NiH battery in a data processing apparatus using the Ni-Cd or NiH battery.